Hmm... thanks for the quick response and the link, Hieronymus! Yeah, after playing around with it a bit more last night I had kinda figured that out. Indeed, you can create all the campaigns you want so long as you use the names and positions of the cities on the campaign map! I'm going to see if there isn't a way to make that limitation work for me somehow...

UPDATE: I have successfully created a 3 scenario campaign that is played through the campaign menu and uses the campaign maps. It's called CAESAR IN EXILE and deals with the period of time between 81 BC when Caesar was forced to flee Rome by the dictator Sulla, and 69 when he secured his first military appointment as Questor of Hispania Ulterior.